This program consists of an integrated set of studies in humans and in a primate model (Macaca arctoides) of the bacteria of dental plaque and the gingival crevic and the host reactions to them which are responsible for producing gingival inflammation and periodontal disease. The individual segments of the program include: analysis of saliva proteins and glycoproteins; enumeration, isolation, and identification of plaque bacteria; isolation of bacterial antigens, and assay with these for cellular and humoral immunity in experimental disease in animals and in humans; analysis of gingival crevice fluids for immune complexes, lymphokines, and complement products; finally, sequential study of qualitative and quantitative variations in these parameters in patients receiving treatment.